1137669-96-5Relevant articles and documents
Nitrosobenzene-Enabled Chiral Phosphoric Acid Catalyzed Enantioselective Construction of Atropisomeric N-Arylbenzimidazoles
An, Qian-Jin,Xia, Wang,Ding, Wei-Yi,Liu, Huan-Huan,Xiang, Shao-Hua,Wang, Yong-Bin,Zhong, Guofu,Tan, Bin
supporting information, p. 24888 - 24893 (2021/10/20)
Described herein is an imidazole ring formation strategy for the synthesis of axially chiral N-arylbenzimidazoles by means of chiral phosphoric acid catalysis. Two sets of conditions were developed to transform two classes of 2-naphthylamine derivatives into structurally diverse N-arylbenzimidazole atropisomers with excellent chemo- and regioselectivity as well as high levels of enantiocontrol. It is worth reflecting on the unique roles played by the nitroso group in this domino reaction. It functions as a linchpin by first offering an electrophilic site (N) for the initial C?N bond formation while the resulting amine performs the nucleophilic addition to form the second C?N bond. Additionally, it could facilitate the final oxidative aromatization as an oxidant. The atropisomeric products could be conveniently elaborated to a series of axially chiral derivatives, enabling the exploitation of N-arylbenzimidazoles for their potential utilities in asymmetric catalysis.
Amino-P Ligands from Iminosugars: New Readily Available and Modular Ligands for Enantioselective Pd-Catalyzed Allylic Substitutions
Borràs, Carlota,Elías-Rodríguez, Pilar,Carmona, Ana T.,Robina, Inmaculada,Pàmies, Oscar,Diéguez, Montserrat
, p. 1682 - 1694 (2018/06/18)
The construction of a novel class of amino-phosphite/phosphinite/phosphine ligands containing a protected pyrrolidine-3,4-diol moiety is presented. These ligands are obtained from readily available sugars. They thus contain the advantages of carbohydrates in terms of selection of the stereogenic carbons, polyfunctional groups able to modulate the electronic and steric properties, and the general good stability of carbohydrate derivatives. They constitute a novel class of P,N-ligands that have been used in the enantioselective allylic substitutions of acyclic and cyclic substrates with varied electronic and steric requirements, using different C- and N-nucleophiles, with high enantioselectivities. Among the three groups of P,N-ligands (amino-P; P = phosphite, phosphinite, and phosphine groups) the new amino-phosphite ligands give the widest substrate and nucleophile scope, including the more challenging hindered linear and cyclic substrates. In particular, for carbohydrate-derived amino-phosphite ligands and linear substrates, high enantioselectivity in the reactions requires an R configuration of the binaphthyl moiety. However, for cyclic substrates both product enantiomers can be reached by setting out the chirality of the binaphthyl phosphite moiety. A detailed investigation of the appropriate Pd intermediates is also presented.
Asymmetric Allylic Alkylation and Hydrogenation with Transition Metal Complexes of Diphosphite Ligands Based on (1S,2S)-Trans-1,2-cyclohexanediol
Pang, Zengbo,Tian, Mi,Li, Haifeng,Wang, Lailai
, p. 893 - 899 (2017/03/24)
Abstract: The preparation of new palladium complexes in situ that were composed of a series of chiral diphosphite ligands, which were derived from (1S,2S)-trans-1,2-cyclohexanediol, have been described. It was found that (1S,2S)-bis[(S)-1,1′-binaphthyl-2,
